[Beer and Pizza]

TNG showed the fundamental flaw of a show with a cast of regulars who will not leave the show. It grows stagnant.

They killed off one main character early in the series, and then nothing.

They should have randomly pulled a name out of a hat each year and told that actor.. "this is the year you get killed off"

That would bring some excitement and unpredictability to a show that otherwise is too predictable as the "immortal" actors can get in any situation without fear of dying.